The Naval Air Systems Command (NAVAIR), Naval Air Station Patuxent River, MD, has awarded definitization modification P00134 on contract N00019-19-C-0010 to Lockheed Martin Corp., Lockheed Martin Aeronautics Co., Fort Worth, Texas, on a sole source basis for an effort to provide the continued development of critical F-35 warfighting development and integration of three unique United Kingdom (UK) / Italian critical weapons capabilities through System Functional Review to Development Test Complete in addition to mission critical data scope for the U.S Air Force, U.S. Navy, U.S. Marine Corps, and F-35 Cooperative Program Partners. As the sole designer, developer, manufacturer, and integrator of the F-35, Lockheed Martin Aeronautics Co. is the only source that possesses the engineering data, technical skills, and requisite knowledge of the design, fabrication, performance, and operational characteristics of the F-35 required to perform the necessary efforts within the required timeframes and without substantial duplication of costs. No other source has the technical qualifications and necessary resources to perform the work described herein, nor will any other supplies or services satisfy the Government's requirements.